Andreas Schwarzlose was a German designer who created several very interesting and unusual handgun designs (in addition to his 1907 heavy machine gun, which was adopted as a standard arm of the Austro-Hungarian military). His first handgun was the model 1898, a short recoil, rotating bolt pistol that was remarkably ahead of its time but failed to sell well. This was followed by this experimental toggled locked 1901 prototype design.

The 1901 Schwarzlose is a toggle-delayed blowback system, but not in the same way as the Luger or Pedersen. It has a unique set of arms that provide a major mechanical disadvantage to delay opening when fired, unlike anything else. It also uses a torsion type of mainspring, which is also quite unusual in handgun design. All in all, a fascinating pistol!

When it failed to become commercially successful, Schwarzlose moved on to his 1908 blow-forward pocket pistol, which (remarkably) was the most successful of all his handguns.